The vessel, named FSO Safer, has been abandoned in the Red Sea off the western coast of Yemen since March 2015 when Houthi rebels took over the region.

The tanker, moored near the Yemeni port of Ras Isa, contains around 1.1 million barrels of petroleum.

That is four times the amount of oil released in the 1989 Exxon Valdez oil spill - widely seen as one of the worst man-made natural disasters in history.

The tanker has been stranded at its present spot since 2015, where locals have used the ship as a make-shift barge.

Sitting for years without maintenance, however, the decrepit vessel is now deteriorating rapidly, risking a global environmental calamity of historic dimensions.

ABANDONED: The vessel, named FSO Safer, has been abandoned in the Red Sea since March 2015 (Image: Supplied)

Explosive gasses are thought to have built up in the decrepit tanker's storage tanks that could rupture any minute, experts said.

The blast would create an "environmental and humanitarian catastrophe" as it sends oil pumping into the sea, according to the UN-recognised Yemeni government.

Depending on the time of year and water currents, a spill from the tanker could quickly leach into the Suez Canal, and might spread as far as the Strait of Hormuz, the UN humanitarian coordinator Mark Lowcock told the UN Security Council.

He said: “I leave it to you to imagine the effect of such a disaster on the environment, shipping lanes and the global economy,” he said, adding “discussions continue to resolve this as quickly as possible.”

DANGER: The tanker contains around 1.1 million barrels of petroleum (Image: Supplied)

The vessel belongs to the country’s state-owned oil firm, the Yemen Oil and Gas Corporation.

Yemen has been crippled by a fractious civil war following the Iran-backed Houthi uprising that swept the pro-Western government into exile in 2015.

A standoff over the Safer and its £64million-worth of oil has meant it has been left to decay - leading to fears it is on the verge of blowing up.

A report for the Atlantic Council think-tank said: "Though a photograph reveals only a ship, known as the Safer, its explosive potential renders it a floating bomb - permanently moored in the Red Sea off Ras Isa."

Mark Lowcock told the UN security council last week: "If the tanker ruptures or explodes, we could see the coastline polluted all along the Red Sea.

'BOMB': The oil tanker described as a “ticking bomb" could explode (Image: Supplied)

"Depending on the time of year and water currents, the spill could reach from Bab-el-Mandeb to the Suez Canal, and potentially as far as the Strait of Hormuz."

The Red Sea has a delicate ecosystem that is home to corals and around 600 species of fish - making it vulnerable to pollution.

The Yemen conflict - seen as a proxy war between Iran through the Houthi and Saudi Arabia through the exiled government - has sparked a humanitarian crisis.

Over 14 million Yemenis depend on international aid - more than half the country's 24 million population.